Diseases of the Plum 325 



gradually enlarge, reaching a diameter of about an 

 eighth of an inch. They then turn darker, the tissues 

 wither, and the entire center usually falls out of the 

 spot, leaving a clean, round hole, which looks as 

 though made with shot from a shotgun. Either the 

 discolored dots with their concentric rings, or the 

 round shot-holes are sufficiently characteristic to en- 

 able anyone to recognize the disease at once. 



Experiments have repeatedly shown the ame- 

 nability of this disease to treatment with the ordinary 

 fungicides. Beach has proved that bordeaux mixture, 

 however, is considerably superior to any other solution 

 in general use. As the result of his extended and 

 thorough experiments he recommends the following 

 course of treatment: "When but two treatments are 

 to be made during the season, let the first be given 

 about ten days after the blossoms fall, that is, usually 

 about May 25 [at Geneva, N. Y.] . It should not be 

 later than June i. Make the second treatment about 

 three weeks after the first. Better results may be ex- 

 pected from three treatments, and three treatments are 

 especially recommended in seasons when the disease is 

 very abundant. Make them as follows: First, about 

 ten days after the blossoms fall; second, about three 

 weeks after the first; third, from three to four weeks 

 after the second." 



Pockets, Bladders, or Curl. The various troubles 

 going under the names of plum pockets, bladders, leaf 

 curl, etc., are mostly very closely allied. They are 

 caused by fungi. These fungi all belong to the genus 

 Exoascus (Taphrina) ; but there are, according to the 

 mycologists, several species.* 



*Atkinson gives the fullest account of these fungi which has been 

 published in this country. He does not take up the practical question of 

 combating them, however. See Cornell Experiment station Bulletin 73. 

 1894- 



